[ShibeSuchBass]

In your price range you can afford a Dayton SUB 1000 or 1200, Micca MB42X or maybe even the Fluance SX6, but I don't know enough about speaker amplifiers to recommend one.  You of course need one that has a line-out/preamp out for a powered sub woofer.

Thanks, I've heard about the Daytons when I was looking around. I only will need an amp if I need one for the set up to work, but I still might get something like a Fiio E10 amp for bass boost. I really do believe in amp bass boost. The E11 I have right now makes a world of difference for bass when I turn on bass boost, and it does not sound like fake bass either, this is all talking about with headphones,but I'm sure it would make a difference with speakers too if I put it right after the source.

E: I really like the Dayton Audio SUB-1200's. This is the only video I could find of them playing music, even though it is two and turned up all the way, I think it would be pretty good, plus they are 12" and go down all the way to 25Hz which is excellent in my book. Its in my price range too, at $125 shipped. On paper, these seem promising and at the top of my list.

 

[ShibeSuchBass]

I would suggest that with a budget of just $300 you are going to struggle, budget sub's tend to be very flabby and not very accurate.  As the saying goes you get what you pay for, I would budget $300 for JUST a sub or not bother and blow my budget on the best speakers you can afford.  A good 6" main driver (or bigger) can give you plenty of bass but it wont be that chest rumbling bass of a club.  My ADAMs are 7" main driver and rumble my room so bad even my teenage daughter complains when she is watching tv in the next room.  

When spending any money on audio gear its worth paying a little more to get some local advice and customer care.  Get on the internet and look up all your local hi-fi and pro audio suppliers, hopefully you will have the chance to pay one or more a visit and do some direct comparisons.  The beauty of active monitors is you dont need the separate amp, and the amps are designed specifically for the drivers in the cabinets, so not only a space saving but no hassle trying to match speakers to amps for efficiency and tonal preference.  

As you are in USA here are some examples of what would fit your budget of $300, disclaimer I have never used this supplier, 
http://www.sweetwater.com/store/detail/LSR305 
http://www.sweetwater.com/store/detail/Rokit5G3
http://www.sweetwater.com/store/detail/ErisE5

All of these come with a 5" driver which is nice for desktop use, as you are sitting pretty close, you can then add a sub later if you think you need it and if funds allow.
All of these brands also have an 8" driver version and the KRK also has a 6" driver too, but will stretch your budget. 

I would say even with some savvy shopping you will struggle to compete on sound quality if you are going to go the route of a t-amp and passive speakers.

Furthermore I do think you under-estimate the capability of modern speakers in terms of range, a sub is not always required.  Maybe I am just getting old  hope that helps

edit: you mentioned a DAC, what is your current source? I assume a PC?  Modern MOBO's can have pretty good on board sound, but it does depend on the model and what other gear is in your system that may cause noise issues.

I know it won't be the best stuff with my budget, but I really don't need anything too high end. It will just be for gaming (I usually use earphones when gaming though), and of course listening to music occasionally. The sources would be my pc of course, and my Galaxy S5. To give you an idea, I am coming from only ever knowing ****ty $10 computer speakers with nonexistent bass, they just produce audio lol. The best I have right now is my Logitech Z313, I know nobody serious on here would consider that good, but I think it's good, only because I have never known better. I think any budget speakers here would crush the Logitech speakers I have, same with the sub. I don't need super crazy subs causing an earthquake, but I would like to feel it. I also would need sub bass, they should go down below 30Hz. Who knows, maybe a pair of speakers can satisfy my need of bass, but on paper, it would not seem to, and it would be nice to just have a sub for the guaranteed bass and sub bass. About a sub, I don't need it to be especially accurate, this will be for far from professional listening, I just want good impactful bass. From what I have put together from some research, it's either a smaller and accurate sub with less bass, or a bigger louder and sloppier sub with impact.

I mentioned a DAC because I don't know if I would need one. The pc source would be from the mobo of course, first sentence has the full list linked. The mobo has a separate circuit for audio that has an amp, signal separation and some other fancy audio stuff. I thought it was gimmicky at first, but couple reviews say it works. The rear speaker port on the I/O is supposedly better because it is direct from the audio circuit on the mobo.

A "studio monitor" can be either passive (unpowered) or active (powered). An active speaker has a power amp built-in, but an active speaker does not. All studio monitors are speakers, but not all speakers are studio monitors. Typically, a studio monitor is designed to work with pro-audio gear, so it might have an XLR or 1/4" unshielded connection. It might also be intended to be used in "near field" - meaning that it's very near the listener (like on a desk) as opposed to be farther away like you might have in a typical home living room.

Thanks for the info, really clarifies things for me. If a studio monitor is for pro gear like in an actual studio, I don't think it would be best for me. When would it be best to get powered speakers/sub or passive?

A question for anyone, is it bad to put your sub under your desk? I read one thing kinda insinuating you should not put your sin under your desk or something. Would it be bad for the desk construction or sub or anything? I guess I believe that may be justified because all the air it's moving and pressure waves or something.

Again to all, keep in mind I am coming from ****ty 10 buck small speakers, my Logitech Z313 system. Then there is my headphones, but I would say that is a different kind of bass, as in its more direct as its right in your ears and such. So I guess my expectations may be low, but I definitely want bass and enough for an average bedroom.

 

[ShibeSuchBass]

For reference, this is one of my favorite tracks and has some of the deepest and lowest bass ive heard yet. The dubstep I listen to is not that trash Skrillex stuff. Then this is some other kind of music I would listen to, less bass, but still very present, more highs and mids prevalent. 

 

[krishtrinity1]

Just buy a Micca MB42X with SMSL SA50,you may not need a subwoofer just give it a listen.Also if you want to go more premium buy the smsl SA50 and Teac LS H265,don't let the rms power fool you,it's the efficiency of the drivers that matters.I can guarantee you will not be disappointed.

 

[Alyus]

  For reference, this is one of my favorite tracks and has some of the deepest and lowest bass ive heard yet. The dubstep I listen to is not that trash Skrillex stuff. Then this is some other kind of music I would listen to, less bass, but still very present, more highs and mids prevalent. 

So what set up did you end up getting after half a year?